The instant invention relates to wrenches and more particularly to an open-end wrench which is operative with an automatic ratcheting action for tightening and loosening hex-headed fastening elements.
Over the years, ratchet wrenches have been found to be extremely effective for tightening and loosening hex-headed fastening elements, such as bolts and machine screws, in a virtually limitless range of applications. In this connection, ratchet wrenches have generally been found to be advantageous from a convenience standpoint, since they do not have to be repositioned on the heads of fastening elements during tightening or loosening operations. Further, ratchet wrenches have been found to be advantageous from a mechanical standpoint, since they permit tightening or loosening operations to be carried out with oscillating motions which generally permit users thereof to apply maximum levels of torque to the heads of fastening elements while nevertheless minimizing the amounts of work required to perform tightening or loosening operations. However, while ratchet-type wrenches have been found to have significant advantages over other types of wrenches, it has been found that they generally require significant amounts of clearance space to enable them to be installed on the heads of fastening elements and thereafter manipulated to rotate the heads of the fastening elements during tightening or loosening operations. In this connection, most of the heretofore available ratchet wrenches have been embodied as either socket-type wrenches or as box-type wrenches, and hence they have required substantial amounts of clearance space around the entire heads of fastening elements on which they are engaged. Further, while attempts have been made to construct ratchet wrenches in other configurations, such as open-end configurations, the only heretofore available openend type wrenches which have been operative with ratcheting actions have required specific user manipulations to provide simulated ratcheting actions, and they have not been operative with truly automatic ratcheting actions, such as normally found in box or socket-type ratchet wrenches.
Open-end type wrenches which represent the closest prior art to the subject invention of which the applicant is aware are disclosed in the U.S. Pat. Nos. to Pehrsson 2,013,065; Falk 2,302,199; Bugge 2,719,448; Israel 2,827,814; Allegraud 3,232,150; Rydell 3,505,915; Evans 3,817,128; Wilson 3,878,741; and Meggs et al 4,065,986. However, while these references disclose a number of wrenches which are rapidly adjustable for engaging hexheaded fastening elements of different sizes, as well as a number of wrenches which are manually operative for providing simulated ratcheting actions, they fail to disclose or suggest an open-end type wrench which is operative with a truly automatic ratcheting action, and hence they are believed to be of only general interest with respect to the subject invention.
The instant invention provides a highly effective openend type ratchet wrench which is operative with an automatic ratcheting action and which can be utilized for effectively and easily manipulating the heads of hex-headed fastening elements in areas where only limited clearance space is available. More specifically, the instant invention provides a ratchet wrench comprising an elongated handle element and a jaw assembly on the handle element including a first jaw portion which is rigidly attached to the handle element , a slide portion which is slidably mounted on the handle element, and a second jaw portion which is mounted on the slide portion and positionable in a predetermined normal position wherein the first and second jaw portions cooperate to define a mouth therebetween for nonrotatably receiving the head of a hex-headed fastening element. The jaw assembly further includes biasing means for biasing the second jaw portion toward the first jaw portion and also toward the adjacent end of the handle element and restricting means for preventing movement of the second jaw portion beyond the normal position thereof in a direction toward the first jaw portion and also in a direction toward the adjacent end of the handle element. The restricting means is further operative for preventing movement of the second jaw portion beyond the normal position in a direction away from the first jaw portion when the sum of the forces applied to the second jaw portion has a net force component which extends in a direction toward the adjacent end of the handle element. The second jaw portion is, however, otherwise movable in a direction away from both the first jaw portion and the adjacent end of the handle element against the force of the biasing means when the sum of the forces applied to the second jaw portion has a net force component which extends outwardly in a direction away from the adjacent end of the handle element. In this connection, it has been found that the forces which are applied to a wrench by the head of a fastening element during a tightening or a loosening operation inherently cause the second jaw portion to be urged toward the adjacent end of the handle element while turning the fastening element in one direction and away from the handle element while turning the fastening element in the opposite direction. Accordingly, when the wrench is received on the head of a fastening element and the wrench is rotated in a first direction wherein the sum of the forces applied to the second jaw portion has a net force component which extends toward the adjacent end of the handle element, the second jaw portion is prevented from being moved outwardly from the first jaw portion by the restricting means and a turning force is applied to the fastening element. However, when the wrench is rotated in an opposite second direction, the sum of the forces applied to the second jaw portion by the head of the fastening element has a net force component which extends in a direction away from the adjacent end of the handle element so that the second jaw portion can be cammed outwardly away from the first jaw portion by the head of the fastening element to enable the head of the fastening element to rotate between the first and second jaw portions.
In the preferred embodiment of the wrench of the subject invention, the first and second jaw portions have substantially flat faces thereon which are disposed in substantially parallel spaced relation when the second jaw portion is in the normal position thereof, and the faces of the first and second jaw portions are engageable with opposite peripheral portions of the head of a fastening element to cause the second jaw portion and the slide portion to be urged toward the adjacent end of the handle element and to thereby prevent the second jaw portion from being moved outwardly when the wrench is rotated in the first direction. The faces on the first and second jaw portions are also engageable with opposite peripheral portions of the head of a fastening element to cause the second jaw portion to be urged outwardly and away from the adjacent end of the handle element when the wrench is rotated in the second direction. The restricting means preferably comprises track means on one of either the handle element or the slide portion and pin means on the other one of the handle element or the slide portion, and the pin means is received in the track means for guiding and restricting the movement of the slide portion relative to the handle element. The track means preferably comprises an elongated aperture in either the handle element or the slide portion which extends angularly outwardly toward the second jaw portion and away from the first jaw portion and forms a seat at one end thereof, and the pin means preferably comprises a pin element which is mounted on the other end of either the handle element or the slide portion so that it travels in the aperture when the slide portion is moved relative to the handle element. Further, the wrench is preferably adapted so that the pin element is receivable in engagement with the seat for preventing movement of the second jaw portion in a direction away from the first jaw portion, and the restricting means preferably further includes a stop which is engageable with the slide portion for preventing the slide portion from pivoting about the pin element to move the second jaw portion away from the first jaw portion when the pin element is received in the seat and the second jaw portion is in the normal position. Accordingly, when the wrench is assembled on the head of a fastening element and turned in the first direction, a net force is applied to the second jaw portion having a component which extends in the direction of the adjacent end of the handle element so that the pin element is urged against the seat to prevent the second jaw portion from being moved outwardly. However, when the wrench is rotated in the opposite second direction, a net force is applied to the second jaw portion having a component which extends in a direction away from the adjacent end of the handle element so that the pin element is disengaged from the seat to enable the second jaw portion to be moved outwardly relative to the first jaw portion and the adjacent end of the handle element. The first and second jaw portions are preferably disposed on opposite sides of a central axis of the jaw assembly, and the aperture is preferably disposed on the same side of the axis as the second jaw portion, whereas the stop is preferably disposed on the same side of the axis as the first jaw portion. The biasing means of the wrench is preferably operative for biasing the slide portion to a position wherein the pin element is received in the seat, and it is preferably postioned so that the main force component of the biasing means is substantially perpendicular to the axis of the jaw assembly. In other words, the biasing means is oriented such, that if broken up into force component vectors, including one vector which is substantially perpendicular to the axis of the jaw assembly, the vector which is substantially perpendicular to the axis of the jaw assembly represents greater than 50% of the biasing means force. The biasing means preferably comprises a spring element which is spaced from the stop, and the spring element preferably biases the slide portion toward a position wherein it is pivoted about the pin element so that it engages the stop and so that the pin element is received in engagement with the seat. The first jaw portion preferably has first and second primary faces and first and second secondary faces thereon, and the second jaw portion preferably has third and fourth primary faces and third and fourth secondary faces formed thereon. The primary faces are preferably sequentially disposed at angles of approximately 120.degree. with respect to each other, and the secondary faces are preferably disposed at angles of approximately 120.degree. with respect to each other and approximately 210.degree. with respect to the adjacent primary faces. Accordingly, when the wrench is received on the head of a fastening element so that sequential sides of the fastening element are positioned in engagement with the first, second, third and fourth primary faces and the wrench is rotated in the second direction, the second jaw portion is cammed outwardly so that the sides of the fastening element are moved into engagement with the first, second, third and fourth secondary faces on the wrench.
Accordingly, it is a primary object of the instant invention to provide an open-end type wrench which is operative with an automatic ratcheting action.
Another object of the instant invention is to provide an effective ratchet wrench which can be utilized for manipulating fastening elements located in areas where space limitations prevent the use of other types of ratchet wrenches.
An even further object of the instant invention is to provide an open-end ratchet wrench having a size which is equivalent to that of a conventional open-end wrench.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.